<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>过渡和转换</title>
    <style>
        div.div1{
            width: 100px;
            height: 100px;
            background: red;
            transition: 3s;
        }
        div.div1:hover{
            width: 300px;
            height: 300px;
            transform: rotate(180deg);
        }
    </style>
</head>
<body>
<div class="div1"></div>
</body>
</html>